In-band call association signaling for a single number destination

In one configuration, the present invention is directed to an enterprise network that includes geographically dislocated first and second network regions and communicating with one another through first and second networks and and respectively comprising first and second gateways and and first and second groupings of trunks. A common electronic address is associated with the second grouping of trunks. A media server is positioned in the first network region that includes an inter-gateway routing agent . The first network region transmits, as part of the establishment of a real-time or near real-time communication between first and second subscribers respectively in the first and second network regions, the common address to the second gateway . After the outgoing communication is answered by the second gateway , the first network region transmits in band to the second gateway a user identifier associated with the second subscriber and/or a phantom user. The user identifier is used to establish the communication with the second subscriber.